The present invention relates to a fluid inlet device for introducing a mixture of liquid and gas into a column. Such a column is any column in which gas and liquid are counter-currently contacted to exchange heat or matter. An example of such a column is a fractionation column and a further example is a vacuum distillation column. In such a column liquid flows, during normal operation, downwards from top to bottom, whereas gas flows upwards from bottom to top. In the specification and in the claims the word xe2x80x98gasxe2x80x99 is used to refer to gas and to vapour.
British patent specification No. 1 119 699 discloses a fluid inlet device for introducing a mixture of liquid and gas into a column provided with an inlet nozzle and a gas/liquid contacting tray arranged below the inlet nozzle.
The known fluid inlet device comprises an inlet device having an inlet end that is in fluid communication with the inlet nozzle of the column, and which inlet device comprises a number of evenly spaced vertical vanes placed one behind the other in the column between a top plate and a bottom plate, wherein each vane comprises an outwardly directed deflecting part.
During normal operation a mixture of gas and liquid is supplied to the inlet nozzle of the column. This mixture then flows through the inlet end into the inlet device. The vanes, arranged on either side of a flow path from the inlet end, deflect the mixture outwardly. The change in the direction of flow causes a first gas-liquid separation. The gas flows upwards in the column, where further contacting with liquid supplied to the top of the column takes place, and the separated liquid falls downwards on the gas/liquid contact tray below the inlet device. On the gas/liquid contact tray, the liquid is contacted with gas flowing upwards from the bottom of the column through the perforations in the tray in order to exchange heat and matter with the gas. This contacting takes place on the bubbling area of the gas/liquid contact tray, which is the area of the tray provided with perforations.
In the known inlet device, the vanes are placed at regular intervals. As a result of this arrangement a uniform distribution of liquid over the gas/liquid contact tray under the inlet device is obtained.
For this reason the known inlet device can be used successfully with a conventional gas/liquid contact tray, such as a counter-current tray without a downcomer or a cross-flow tray having a single downcomer at one side of the tray. In a counter-current tray without a downcomer the bubbling area or active area extends over the entire area of the tray, and in a cross-flow tray the bubbling area extends up to the downcomer.
However, there is a trend to use, in stead of a single-downcomer tray, a gas/liquid contact tray with more than one downcomer. Such a multi-downcomer tray is provided with elongated downcomers arranged parallel to each other, wherein the bubbling area is defined between adjacent elongated downcomers.
When the known inlet device is used in combination with such a multi-downcomer tray, not all liquid will fall on the bubbling area. And thus the efficiency of the gas/liquid contact tray is reduced.
It is an object of the present invention to provide a fluid inlet device that can be used in combination with a multi-downcomer tray.
To this end the fluid inlet device for introducing a mixture of liquid and gas into a column provided with an inlet nozzle and with a horizontal gas/liquid contact tray arranged in the column below the inlet nozzle provided with a number of elongated downcomers between which bubbling areas are located, according to the present invention comprises an inlet end that is in fluid communication with the inlet nozzle of the column, a number of vertical vanes placed one behind the other in the column between a top plate and a bottom plate, wherein each vane comprises two interconnected parts, an intercepting part and an outwardly directed deflecting part, wherein the intercepting part extends to the inlet end of the inlet device, and wherein an outlet channel defined by the deflecting parts of two adjacent vanes opens above a bubbling area of the contact tray.